ESTRO 36 Abstract Book

S362 ESTRO 36 _______________________________________________________________________________________________

PO-0693 Stereotactic radiotherapy in hepatocellular carcinoma: a systematic review L. Manuzzi 1,2 , A. Farioli 3 , G. Macchia 4 , F. Deodato 4 , S. Cilla 5 , V. Picardi 4 , F. Cellini 6 , G.C. Mattiucci 6 , A.D. Andrulli 7 , A. Guido 1 , S. Cammelli 1 , A. Arcelli 1,8 , A. Cortesi 1,9 , G. Tolento 1 , G. Siepe 1 , M. Ferioli 1 , M. Buwenge 1 , G.P. Frezza 8 , L. Fuccio 3 , A.G. Morganti 1 1 University of Bologna, Radiation Oncology Center- Department of Experimental- Diagnostic and Speciality Medicine - DIMES, Bologna, Italy 2 University of Bologna, Oncology Center- Department of Experimental- Diagnostic and Speciality Medicine - DIMES, Bologna, Italy 3 University of Bologna, Department of Medical and Surgical Sciences - DIMEC, Bologna, Italy 4 Fondazione di Ricerca e Cura "Giovanni Paolo II", Radiotherapy Unit, Campobasso, Italy 5 Fondazione di Ricerca e Cura "Giovanni Paolo II", Medical Physics Unit, Campobasso, Italy 6 Policlinico Universitario "A. Gemelli"- Università Cattolica del Sacro Cuore, Department of Radiotherapy, Rome, Italy 7 IRCCS- CROB, Department of Radiotherapy, Rionero in Vulture, Italy 8 Ospedale Bellaria, Radiotherapy Department, Bologna, Italy 9 Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori IRST- IRCCS, Radiotherapy Department, Ravenna, Italy Purpose or Objective Hepatocellular carcinoma (HCC) is a leading cause of cancer death. Experience with stereotactic body radiotherapy (SBRT) for HCC is increasing due to the possibility to deliver ablative doses in few fractions with low rates of toxicity and excellent local control. Furthermore, SBRT can be used in patients unsuitable for other conventional therapies. However, the better way to treat HCC with SBRT has not been defined. Therefore, aim of this analysis was to systematically review the available literature to evaluate treatment and other factors correlated with patients outcome. Material and Methods Literature search was made in PubMed database. We also checked the references list of five reviews published in the last two year. We included randomized trials or not, excluding case series with less than 8 patients, case reports, and reviews. Only studies published in English were included in this review. The primary endpoint was duration of survival in overall population after SBRT measured by 1-year and 2-year survival rate. Secondary endpoint was toxicity (acute or late) reported as grade ≥ 3 toxicity rate. Results Through the evaluation of titles and abstracts, we selected 70 records. At the end of the screening we included 22 papers fulfilling the inclusion criteria amounting to 1093 patients. All selected studies were published from 2006 to 2015. One-year OS ranged from 23% to 100% (median 75%) while 2-year OS from 23.3% to 100% (median 59%). Twenty records reported toxicity. G ≥ 3 toxicity range was 0%-37% (median: 13%). We performed a meta-regression analysis in order to explore whether 1y- OS is correlated to the value of some explanatory variables ( Table 1 ). We observed a direct association between 1-y OS and median age (p=0.004, R²=0.31) as well as the presence of solitary lesion (p=0.033, R²=0.43), vascular invasion (p<0.001 with R²=0.87) and median tumor size (p<0.001 and R²=0.69). Considering the variables related to treatment, EQD 2 (α/β=10) affected 1-y OS very significantly (p <0.001 and R²=0.72).

Conclusion Use of higher EQD 2

is correlated with improved outcome in HCC treated with SBRT. Prognosis is worse in patients with older age, multiple lesions, larger tumor, and vascular invasion. PO-0694 Post-operative Intensity-Modulated hypofractionated Image-Guided Radiotherapy in cholangiocarcinoma N. Slim 1 , B. Noris Chiorda 1 , C. Gumina 1 , G.M. Cattaneo 2 , M. Reni 3 , L. Aldrighetti 4 , A.M. Deli 1 , F. Zerbetto 1 , P. Passoni 1 , N. Di Muzio 1 1 San Raffaele Scientific Institute- Milano- Italy, Radiotherapy, Milan, Italy 2 San Raffaele Scientific Institute- Milano- Italy, Medical Physics, Milan, Italy 3 San Raffaele Scientific Institute- Milano- Italy, Medical Oncology, Milan, Italy 4 San Raffaele Scientific Institute- Milano- Italy, Surgery, Milan, Italy Purpose or Objective To evaluate feasibility of post-operative intensity modulated hypofractionated image-guided radiotherapy (Hypo-IGRT) in patients (pts) with extra-hepatic cholangiocarcinoma. Background: we previously tested Hypo- IGRT in pts with locally advanced pancreatic cancer. The dose of 44.25 Gy in 15 fractions to the whole tumor was feasible and safe (Int J Radiation Oncol Biol Phys, Vol. 87, No. 5, pp. 1000- 1006, 2013). Material and Methods After surgery, pts with histologically proven perihilar and distal cholangiocarcinoma were eligible for this study. Simulation consisted in contrast-enhanced computed tomography (c-e-CT) or 18 F-FDG CT/PET (CTPET) or when possible four-dimensional c-e CT (4D c-e CT), Clinical Target Volume (CTV) consisted in surgical bed and regional lymph-nodes. In Klatskin tumor CTV was defined as the section liver margin and hepatic hilum; the R1 site was identified combining pathological data and surgeon indications. In distal cholangiocarcinoma CTV consisted in the new anastomosis between the biliary tree and the small intestine. The planning target volume (PTV) was defined with standard margins, except in pts who underwent 4D c-e CT where a margin of 5 mm was added isotropically at CTV. Median delivered dose of RT was 44.25 Gy (40 Gy-48 Gy) in 15 fractions on PTV and was delivered with Volumetric